Dynamics of radiocesium in paddy-field ecosystems including its transfer to rice

2018 Fiscal Year Final Research Report

• Project/Area Number: 25252006
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Crop production science
• Research Institution: The University of Tokyo
• Principal Investigator: NEMOTO Keisuke 東京大学, 大学院農学生命科学研究科(農学部), 教授 (40211461)
• Research Collaborator: KUROSAWA Takashi 伊達市産業部, 農林整備課, 課長
• Project Period (FY): 2013-04-01 – 2018-03-31
• Keywords: 放射性セシウム / 水田 / イネ

Outline of Final Research Achievements

Rice contaminated with high concentrations of radiocesium was found in some local areas after the nuclear accident in Fukushima in 2011. Since 2012, we have continued to cultivate rice experimentally in paddy fields in one of these areas, Oguni, to trace the annual change of radiocesium uptake. To our surprise, the radiocesium concentration in rice cultivated in the experimental paddy fields has seen only a little change since 2013. One of the reason for this is that radiocesium fixation in soil has hardly progressed in these paddy fields. On the other hand, the inflow of radiocesium via irrigation water to the paddy fields has been much lower than the amount absorbed by rice since 2013. Of course, not all paddy fields in Fukushima are in the same situation: our pot experiments showed that parent material of the soil is the most important factors for uptake in rice grown in different areas.

Free Research Field

栽培学

Academic Significance and Societal Importance of the Research Achievements

水田地帯が原発被害を被った事例は、今回の福島が史上初である。その中でも、吸収抑制対策を一切施していない農家水田でモニタリングを継続した研究事例は、本研究がほとんど唯一ではないかと考えられる。本研究を通じて得られた成果は、福島県伊達市を中心に施策に活用されてきた。本研究結果を踏まえ、稲セシウム吸収のリスクマップ作成を今現在も進めており、その成果は将来にわたって福島の食の安全に資するものと考えている。